Scaffold frames are a series of horizontal and vertical scaffold frame members that connect together to create a raised working platform. The overall structure is supported by the vertical scaffold members contacting the support surface, such as the ground.
Scaffold frames can be constructed from tube and clamp frame members, or from system scaffold members (modular scaffold systems). In system scaffolds, the vertical scaffold members are coupled to horizontal scaffold members at a scaffold joint. A modular scaffold joint comprises a connector on the vertical scaffold member 3000 that is designed to couple or mate with a connector on a horizontal scaffold member, thereby joining together a horizontal and vertical scaffold member 2010. Horizontal scaffold members will be referred to in general as “horizontals,” while vertical scaffold members will be referred to generally as “verticals” irrespective of the joint/connector type.
One type of modular scaffold joint uses an end connector positioned on the end of a horizontal member, where the end connector has a lip or hook section 3001. The lip sections are designed to engage or rest on the corresponding vertical joint connector, such as an upstanding cup or an annular ring positioned 3003 on a vertical scaffold member 3010. One such joint is disclosed in U.S. Pat. No. 4,445,307, shown in FIG. 11, which discloses a connector positioned on a horizontal scaffold member, where the connector has two vertically spaced hook sections 3001.
These hook sections couple with two vertically spaced upstanding cup or ring members 3003 located on the vertical scaffold member 3001. To lock the joint in place, the connector includes a wedge 3100 (a form of a moveable latch member 2000) that is driven (generally by a hammer) into position below the upper ring member, thereby wedging the ring against the end connector hood section, latching the horizontal member to the vertical member. This type of connector is referred to as a Safway connector (see attached FIG. 11). As used herein, “latching” refers to the action of engaging a horizontal member to a vertical member, where the action of latching resists dislodgement of the horizontal member from the vertical member from an upwardly directed force.
Another cup type of latching connector is disclosed in U.S. Pat. Nos. 5,078,532 and 5,028,164 and in U.S. application Ser. No. 12/489,166 all hereby incorporated by reference (see FIG. 12). These patents also show an end connector positioned on a horizontal scaffold member, where the connector has two vertically spaced hooked sections 3001 that couple with two vertically spaced upstanding cup or ring members 3003 located on the vertical scaffold member 3010. In this device, the hooked sections engage the top edge of the cup, and a pivoting member or latch 3400, (the pivoting latch 3400 is another type of movable latch member 2000) positioned on the horizontal end connector, is pivoted into position below the cup member. The latch member 3400 has a distal end extending beyond the housing, shaped to allow for placement of the distal end beneath a cup positioned on a vertical scaffold member. Hence, when latched, the cup 3003 is trapped between the hook engagement sections of the connector housing and the distal end of the latch member 3400 (see FIG. 12A). The latch pivots on a pivot pin, and can be spring loaded to bias the latch into a locking or actuated position. This type of connector is referred to as an Excel connector (see attached FIG. 12). Single cup embodiments are also possible, such as shown in U.S. Pat. No. 7,048,093. Other cup type latching mechanism are in the prior art, including U.S. Pat. No. 4,369,859.
Another “cup” type of latching mechanism is disclosed in U.S. application Ser. No. 11/738,273, filed Apr. 20, 2007 (hereby incorporated by reference)(not shown). This application teaches a horizontal scaffold member having an end connector with two hook or engagement areas, each designed to couple with a cup on a vertical member. The connector includes an upper and a lower latch, each the respective upper and lower coupled ring or cup members. The two latches are mechanically coupled allowing for single action operation to engage or disengage both latches simultaneously. In general, a system scaffold using a cup on the vertical member with a latch on the horizontal scaffold member (whether slidable or pivotable, (as a type of movable latch member 2000) will be referred to as a cup/latch scaffold system. This is also in the scope of an Excel connector.
Another cup-type of latching connector is disclosed in U.S. Pat. No. 3,992,118 (commonly referred to as the Cuplock system)(see FIG. 10). As disclosed in this patent (see particularly FIGS. 3 and 4 of this patent), the vertical scaffold member (generally a pipe) has a fixed annular ring 10 forming an upstanding cup surrounding the vertical member with upward facing annular channel. Positioned above this upstanding cup at a set height is a lug 20. Slidably and rotationally positioned on the vertical scaffold member above this fixed cup, is a reverse cup (a cup facing downwardly) 14 that has a downward facing annular channel (the rotatable cup is another type of movable latch member 2000), and an outward projection 18 in the cup wall that forms a slot 17. This slot accommodates the lug 20, so that the reverse cup, with the slot aligned with the lug, can slide past the lug, and if the slot is not aligned with the lug, the reverse cup 14 cannot slide past the lug 20 (see FIG. 10A). The corresponding horizontal scaffold member (generally a pipe) has at each end, an upward facing ear or tongue and a downward facing ear or tongue (not shown). Each respective tongue is shaped to fit in the annular channel formed in the respective upward and reverse cup. To assemble a joint, the downward tongue on the horizontal member is positioned in the upward annular channel of the upstanding cup. The reverse cup is then slid down the vertical member, past the lug 20 (by proper alignment of the slot 17), to capture the upstanding tongue within the downward facing annular on the reverse cup. The reverse cup 14 is then rotated on the vertical horizontal member until the slot 17 is not aligned with lug 20, thereby “locking” the tongues of the horizontal between the upstanding cup, and the reverse cup (hence the name cuplock)(the rotating cup is another form of movable latch member 2000). (See attached FIG. 10). Instead of upstanding cups, a flat annular ring with openings in the ring may be used as the vertical connector on the vertical scaffold member, to couple to a connector on a horizontal scaffold member. Examples of annular ring/connector systems are shown in U.S. Pat. Nos. 4,273,463; 6,027,276; 5,961,240; 5,605,204; 4,840,513; and PCT publication number WO 2011/094351. All of which are hereby incorporated by reference. These systems are generally referred to as wedge or pinlock scaffold systems, (for an example, see FIG. 9). The pinlock system relies upon a wedge or pin 4000 being slidable (generally hammer driven) through the horizontal end connector and rosette 4010 (the slidable pin is another type of movable latch member 2000). For instance, the joint of U.S. Pat. No. 5,961,240 (see FIG. 1 of that patent, attached as FIG. 9 hereto), uses rosette rings 4010—positioned on a vertical scaffold member. The ring 4010 has a series of openings 4022 therethrough. The horizontal end connector is a body with a horizontal slot or mouth in the body to accommodate the rosette ring. Slidably positioned on the horizontal end connector is a pin 4000, which is vertically slidable through a vertical slot and in the connector body (the slidable pin 4000 is another form of a moveable latch member 2000). In joining a vertical member to a horizontal member, the rosette 4010 is slid into the mouth of the horizontal connector, with an opening 4010 in the rosette aligned with the vertical slot in the end connector. The pin 4000 is then rotated upwardly, and then through the vertical slots, which wedges and holds the horizontal member to the vertical member.
System scaffolds are used to allow for ease of erection of scaffold platforms. However, in some instances, it is not possible to erect a horizontal scaffold platform where the horizontal scaffold members are supported on four (or more) corners by downwardly extending ground supported vertical scaffold members. For instance, an elevated working surface may be needed that is connected to a self-standing scaffold structure, but where the platform is offset or cantilevered from the scaffold frame structure in order to extend the working platform over a structure (such as a tank). An offset working surface may be created by using a triangular shaped frame member connected to the scaffold frame structure (generally, two vertical members of the frame) to create an offset “knee out” structure that will support a cantilevered horizontal working surface. One such structure is shown in U.S. application Ser. No. 12/824,314 filed on Jun. 28, 2010, hereby incorporated by reference. However, when the offset working surface needs to extend more than about ten feet from the scaffold frame, a knee out support structure may not be feasible.
If the working environment includes overhead structures (often seen in bridge and offshore platforms), offset scaffold working surfaces with long platforms can be constructed by suspending the remote end (or intermediate portion) of the offset extended platform from the overhead structure. The suspended offset scaffold working surface makes long extended platforms feasible, but construction is arduous and dangerous. One method of erecting such an offset and suspended platform is as follows. A self-standing scaffold structure is constructed adjacent to the overheard structure, with a working surface positioned at the desired height for the offset platform. From this working surface, a worker will couple an outwardly extending horizontal member to one of the vertical legs of the scaffold, to form an outwardly extending horizontal member supported only at one end by the couple to the vertical scaffold member. Placement of the extended horizontal, for instance, an eight foot long horizontal member, is awkward due to the weight of the horizontal member, and the fact that the horizontal member must be held in position perpendicular to the vertical member in order to couple to the vertical member, thus presenting large torque forces during installation. With a horizontal extending outwardly, a worker would tie off to the scaffold structure, and walk out on the extended horizontal (which is coupled to the scaffold frame at only one end). The worker would then connect a vertical to the free end of the horizontal, and then support the vertical from the overhead structure (such as by tying a rope or chain between the overhead structure and the vertical). The worker would return to the platform, and install a second outwardly extending horizontal, and similarly, attach a vertical to the remote end of this horizontal, and suspend this vertical from the overhead structure. Scaffold planks are then laid over the two suspended horizontals, creating a deck or working surface. A worker would then take a third horizontal, and connect the two suspended verticals to form a more rigid support frame for the working surface. Handrails can then be installed as desired between the verticals of the scaffold main frame and the suspended verticals.
As can be seen, this erection method requires a rigid joint between the horizontal and vertical scaffold member to allow a worker to safely walk out on an extended horizontal. For this reason, the preferred joint for this structure is the pinlock system, such as shown in U.S. Pat. No. 5,961,240, (one embodiment of a pinlock is shown in FIG. 9) as a tight joint is needed to support a worker while working out on the extended horizontal. During the construction, the worker will generally be tied off to the overhead structure. However, even tied off, the procedure is dangerous and awkward. To join a horizontal to a vertical, the horizontal member must be held at a right angle to the vertical to allow the horizontal connector to couple to the vertical rosette or cup. This is difficult to accomplish due to the weight of the horizontal, and the length of the horizontal (7-10) feet. A safer apparatus and method of assembly is needed for building offset suspended scaffold decks.
Collectively, cups and rosettes, or other types of annular members on the vertical scaffold member used to couple to a horizontal end connector will be referred to collectively as annular members.